SIPP calculator
What your SIPP contributions are worth once basic-rate relief is added, what the pot compounds to on an assumption you choose, and what is left after the tax-free share and the income tax on the rest.
Calculator
The current value, including anything transferred in from an old workplace pension. Leave it at nothing if you are starting from scratch.
The amount leaving your bank account — the direct debit, not the figure on your statement. Your provider adds basic-rate relief on top of it, so £500.00 a month becomes £625.00 in the pension.
Salary or self-employed profit, before the contribution. It decides how much relief you get above the basic rate — and whether you have to claim any of it — and it caps how much you can get relief on at all.
The state pension, a defined benefit pension, rental profit — anything taxable in that year. The pot is taxed on top of it, so this changes the tax on it substantially. Taxing a pot in isolation is right only for somebody with no other income at all.
There is no right answer here and this calculator does not suggest one. Whatever you enter is applied every single year, which is not how returns arrive — see the note under the answer.
A percentage of the value, taken every month. It grows as the pot does and takes its largest bite in the final years, which is why it is worth far more than it looks over a long term. Fund charges are separate and are not included.
Whole years. You cannot normally take anything from a pension before the minimum pension age, which is not modelled here and is rising.
Income tax is devolved, so the relief above the basic rate differs in Scotland — and so does the tax on the pot at the other end. The relief your provider adds is the basic rate wherever you live.
Used for both ends: the relief on this year’s contribution and the tax on the pot. Applying today’s rates to a withdrawal decades away is an assumption, not a rate — the rules will change, and this page says so rather than pretending otherwise.
What the SIPP is worth, and what tax it meets at each end
£495,012.74 in the SIPP after 25 years
Of which £123,753.19 could be taken free of income tax and £371,259.55 is taxable when it is taken.
The pot figure is not a forecast. It is what 5.00% a year, applied to every single year and with a 0.45% charge taken every month, compounds to. Nothing grows at the same rate every year, and the order returns arrive in changes the outcome even when the average does not. Treat it as a way of comparing two plans, not as a balance. The tax figures below it are exact given that pot — they use rates checked against gov.uk — and the pot is an assumption, so the tax inherits the assumption whole.
What your contribution is really costing you
| Leaves your account each month | £500.00 |
|---|---|
| Lands in the SIPP each month | £625.00 |
| Into the SIPP over a year | £7,500.00 |
| Added by your provider, reclaimed from HMRC | £1,500.00 |
| Further relief, which you have to claim yourself | £3,000.00 |
| A year in the SIPP actually costs you | £3,000.00 |
£3,000.00 of that relief will not arrive on its own. A SIPP is a relief-at-source scheme: the provider reclaims the basic rate and adds it to the pot, and anything above the basic rate reaches you only through a Self Assessment return or a tax code adjustment. It does not appear on a pension statement and nothing prompts it. It also does not go into the pot unless you put it there — it comes back to you as tax you did not have to pay, so the projection below counts only the money that actually reached the SIPP. The pension tax relief calculator takes that apart.
Where the pot came from
| What you started with, plus your own direct debits | £200,000.00 |
|---|---|
| Basic-rate relief added by the provider over the term | £37,500.00 |
| Growth, on your assumption | £283,735.42 |
| Charges taken over the term | −£26,222.68 |
| The pot at the end | £495,012.74 |
Read those four lines as four different kinds of number. The first is money you will actually hand over. The second is a rule, and rules change. The third is the assumption you typed and is the only line that could turn out to be anything at all — including negative. The fourth is the one certainty working against you: a percentage of the value, taken every month, growing as the pot does and taking its largest bite in the final years.
What it is worth when you take it
| The pot | £495,012.74 |
|---|---|
| Tax-free cash, at 25.00% of the pot | £123,753.19 |
| Taxable when taken | £371,259.55 |
| Income tax if you took all of that in one year, on top of £12,000.00 of other income | £158,669.80 |
| Left after that tax | £336,342.94 |
Taking the whole of it in one tax year is the expensive way, and it is the one the figure above prices. The taxable part is stacked on your other income for that year, so a pot of this size runs up through every band and takes the personal allowance with it — this is income tax at 45.00% on the next pound, against 0.00% on your other income alone. Drawing it over several years keeps more of it in the lower bands, which is what a drawdown arrangement is for; the pension drawdown calculator prices that instead, and this page does not.
The tax-free share is 25.00% of the pot, and there is a cap on it that this calculator does not apply. On a pot large enough to reach that cap the tax-free figure above is too high and the tax too low — the direction that costs you money — so check the lump sum allowance on gov.uk before relying on it. Everything on this line also assumes today’s rates apply in 25 years, which nobody can promise.
The same plan, over other terms
£625.00 a month into the SIPP — your £500.00 plus the relief your provider adds — on top of £50,000, growing at 5.00% a year with a 0.45% charge, in England or Northern Ireland.
| Term | Into the SIPP | Growth | The pot | Tax-free share |
|---|---|---|---|---|
| 5 years | £37,500.00 | £18,673.72 | £104,447.89 | £26,111.97 |
| 10 years | £75,000.00 | £52,218.40 | £172,392.39 | £43,098.10 |
| 15 years | £112,500.00 | £104,320.20 | £257,178.94 | £64,294.74 |
| 20 years | £150,000.00 | £179,579.17 | £362,982.50 | £90,745.63 |
| 25 years | £187,500.00 | £283,735.42 | £495,012.74 | £123,753.19 |
| 30 years | £225,000.00 | £423,952.10 | £659,770.70 | £164,942.68 |
The contribution column rises in a straight line and the pot column does not. That gap is the whole of the compounding argument, and it is also the whole of the assumption: every figure in the growth column is what a constant rate would have produced, and no rate is constant. The same table at a rate of nothing would show the contribution column and the pot column moving together.
Six things this figure does not know
A fixed rate every year is not how returns arrive
The pot is what 5.00% a year compounds to, applied to every year without exception. Real returns arrive in an order, and the order changes the outcome even when the average does not — badly, and most of all once money is being taken out. Nothing here is a forecast, a projection or a promise; it is arithmetic on an assumption you supplied.
It does not apply the cap on tax-free cash
The tax-free share is 25.00% of the pot, and there is an allowance capping the total that can be taken tax-free across all your pensions. This calculator does not hold that figure and cannot apply it, so on a pot large enough to reach it the tax-free amount above is too high. Check it on gov.uk.
It does not check the annual allowance
There is a limit on how much can go into pensions each year with tax relief, it counts employer contributions as well as your own, and it is reduced for high earners. This page applies the limit on relief — the greater of your relevant UK earnings and the basic amount — and not that one. The pension contribution calculator works the annual allowance out.
It prices today’s rules applied to a date decades away
Both ends of this page use the rates and allowances for the tax year you chose: the relief on this year’s contribution, and the tax on a pot you take in 25 years. The second of those is an assumption rather than a rate. Tax rules, allowances and the minimum pension age have all changed repeatedly and will change again — and the minimum pension age is not modelled here at all, so this page will happily price a withdrawal you would not be allowed to make.
It is one contribution, held flat, with no other pension anywhere
The monthly figure is the same every month for the whole term, with no increase for inflation or promotion and no gaps. There is no employer contribution, no other pension, no state pension in the pot, no transfer in and out, and no lump sum. Your income is held at today’s figure for the relief calculation, and only this year’s relief is priced — a page that multiplied one year of relief by the term would be claiming that today’s rates and today’s income hold for the whole of it.
Charges here are one number, and a real account has several
The charge above is a percentage of the value, taken monthly. Real accounts add fund charges, dealing costs, foreign exchange spreads and sometimes a flat fee, and some cap the percentage above a certain value. None of that is modelled, and each of them makes the pot smaller than the figure shown.
Worked example: the same SIPP contribution, three plans
Two people pay the same £300 a month into a SIPP. One starts 15 years earlier and ends with £186,569.70 more — having paid in only £54,000.00 more. Same contribution, same assumption, same charge. Only the length of the run differs.
Ade pays in for 30 years on £45,000 of income. £300.00 leaves his account each month and £375.00 lands in the SIPP, because his provider reclaims basic-rate relief and adds it. Over the term £135,000.00 goes in, of which £27,000.00 is relief he never paid, and on an assumption of 5.00% a year the pot reaches £282,580.85 after £15,028.18 of charges.
Bea does exactly the same for 15 years. She pays in £67,500.00 — £67,500.00 less than Ade — and reaches £96,011.15. The contribution column is halved and the pot is not, because the years Ade has that Bea does not are the years his largest balance is compounding.
Chidi earns £110,000 and pays in the identical £300.00 a month. His pot is the same as Ade’s — £282,580.85 — because the pension does not care what he earns. What differs is the cost: a year’s contribution costs Ade £3,600.00 and costs Chidi £1,800.00, because his income sits in the range where a contribution also restores personal allowance that had been withdrawn. £1,800.00 of Chidi’s relief does not arrive on its own — it comes back through a tax return, and it does not go into the pension unless he puts it there.
| Figure | Ade, 30 years | Bea, 15 years | Chidi, 30 years |
|---|---|---|---|
| Their own direct debits | £108,000.00 | £54,000.00 | £108,000.00 |
| Relief added at source | £27,000.00 | £13,500.00 | £27,000.00 |
| Growth, on the assumption | £162,609.03 | £31,414.50 | £162,609.03 |
| A year’s contribution costs them | £3,600.00 | £3,600.00 | £1,800.00 |
| The pot | £282,580.85 | £96,011.15 | £282,580.85 |
| Tax-free share of it | £70,645.21 | £24,002.79 | £70,645.21 |
Every pot figure in that table is an assumption compounded rather than a balance. The relief figures beside them are not: those use rates checked against gov.uk, and they are the only part of the table that does not depend on a return nobody can promise. The tax-free share is a statutory percentage of a number that is a guess — exact arithmetic over an assumption, which is worth saying plainly because it looks like the most solid figure on the page and is not.
Methodology and sources
The calculation, in order
- Gross up the contribution. What leaves your account is divided by one less the basic rate to get what lands in the pension — £500.00 becomes £625.00 a month. The relief is measured against the gross figure rather than added to the net one, and getting that backwards is the most common error in this area.
- Work out the relief on a year of contributions by computing your income tax twice, with and without them, and adding what the provider reclaims. Relief is capped at the greater of your relevant UK earnings and £3,600.
- Project the pot forward with the grossed-up contribution going in monthly at the start of each month, growth applied monthly at a rate that compounds to the annual figure you entered, and the charge taken monthly on the value.
- Split the final pot at the statutory tax-free rate of 25.00%.
- Tax the rest as income in one year, stacked on your other income for that year — the position with it, less the position without it.
Two engines, two different kinds of claim, and they must not be allowed to borrow each other’s credibility. Steps 1, 2, 4 and 5 use rates, thresholds and allowances published by government and checked against gov.uk. Step 3 uses no published figure at all: it is arithmetic on an assumption you supplied, and a fixed-rate projection is not a forecast — nothing grows at the same rate every year, and the order returns arrive in changes the outcome even when the average does not. Step 5 is the awkward one, because it is statutory arithmetic applied to a figure step 3 invented. The tax is exact given the pot; the pot is a guess; so the tax inherits the guess whole.
Rates, allowances and conventions
| Figure | 2025/26 | 2026/27 |
|---|---|---|
| Tax-free share of a pension pot | 25.00% | 25.00% |
| Most a non-earner can get relief on | £3,600 | £3,600 |
| Personal allowance | £12,570 | £12,570 |
| Personal allowance taper starts at | £100,000 | £100,000 |
| Income tax bands — England, Wales and Northern Ireland | Basic rate 20.00% from £0; Higher rate 40.00% from £37,700; Additional rate 45.00% from £125,140 | Basic rate 20.00% from £0; Higher rate 40.00% from £37,700; Additional rate 45.00% from £125,140 |
| Income tax bands — Scotland | Starter rate 19.00% from £0; Basic rate 20.00% from £2,827; Intermediate rate 21.00% from £14,921; Higher rate 42.00% from £31,092; Advanced rate 45.00% from £62,430; Top rate 48.00% from £125,140 | Starter rate 19.00% from £0; Basic rate 20.00% from £3,967; Intermediate rate 21.00% from £16,956; Higher rate 42.00% from £31,092; Advanced rate 45.00% from £62,430; Top rate 48.00% from £125,140 |
The projection’s own conventions carry no rate at all and are stated instead: monthly periods, contributions at the start of each month, growth converted from your annual figure on an effective basis so that twelve monthly steps compound to exactly the rate you typed, and the charge taken monthly on the value. A nominal basis would compound to more than the number you entered, which is the unstated convention this site exists to correct.
What this page does not model
- The cap on tax-free cash. The rate is statutory and verified; the allowance capping it is not held by this software, so a large pot shows too much tax-free cash and too little tax.
- The annual allowance, its taper for high earners, and carry forward. Only the limit on relief is applied.
- The minimum pension age, which is rising, and any protected pension age. The page will price a withdrawal at a term you are not allowed to take one at.
- Drawing the pot over several years, which keeps more of it in the lower bands and is what most people actually do.
- Employer contributions, other pensions, contribution increases, gaps, transfers, fund charges and dealing costs.
Where the figures come from
- gov.uk — Tax on your private pension contributions: pension tax relief
- gov.uk — Tax when you get a pension
- HMRC — Pensions Tax Manual PTM044220, relief at source
- gov.uk — Pension annual allowance
- gov.uk — Income tax rates and allowances: current and past
The rates and allowances in the table above were verified against gov.uk on 12 August 2026. That check covers the published figures this page computes with. It does not verify any result the page produces, and it has not yet been signed off by a person — the verification recorded in the source repository is an automated one. It covers nothing about the projection, which contains no published figure and makes an arithmetic claim only. Check anything that matters against gov.uk or with an accountant or a regulated adviser.
Every calculation runs in your browser. There is no application server and no database, so nothing you type is transmitted or stored. A share link is the exception: it carries your figures in the URL. More on what that means. Information, not advice: this page names no provider, ranks no product and recommends no course of action.
Frequently asked questions
- How does tax relief on a SIPP work?
A SIPP is a relief-at-source scheme. You pay in out of income that has already been taxed and the provider reclaims basic-rate relief from HMRC and adds it to your pot, so £500.00 leaving your account becomes £625.00 in the SIPP. The grossing-up is a division rather than an addition: the relief is measured against the amount that ends up in the pension, not added on top of the amount you paid. If you pay tax above the basic rate there is more relief available, and it does not arrive on its own — it is given by increasing your rate limits, which reaches you through a Self Assessment return or a tax code change, and it comes back to you rather than going into the pot.
- How much will my SIPP be worth?
Nobody knows, and this calculator does not pretend to. What it shows is what a single growth rate, applied to every year without exception, compounds to — with your contributions grossed up and a charge taken monthly on the value. On the figures it opens with, £625.00 a month into £50,000 at 5.00% a year for 25 years reaches £495,012.74, of which £283,735.42 is the assumption and £200,000.00 is money you actually paid in. Real returns arrive in an order, and the order changes the outcome even when the average does not. Use it to compare two plans, not to predict a balance.
- How much can I take out of a SIPP tax-free?
25.00% of the pot, with the rest taxable as income when you take it. There is also an allowance capping the total tax-free cash you can take across all your pensions, and this calculator does not hold that figure and does not apply it — so on a pot large enough to reach it, the tax-free amount shown here is too high and the tax too low. On the figures the page opens with, £123,753.19 would be tax-free and £371,259.55 taxable. Check the lump sum allowance on gov.uk before relying on any of it.
- How much tax will I pay when I take my SIPP?
It depends entirely on how you take it and on what else you have coming in that year. This page prices the expensive version: the whole taxable part in one tax year, stacked on your other income. On the default figures that is £158,669.80 of income tax on £371,259.55, leaving £336,342.94 of the pot — because a pot that size taken at once runs up through every band and takes the personal allowance with it. Drawing it over several years keeps more of it in the lower bands, which is what drawdown is for and what the pension drawdown calculator on this site prices instead.
- Can I get higher-rate tax relief on a SIPP?
Yes, if you pay tax above the basic rate — but you have to claim it, and a great deal of it is never claimed. Your provider only ever reclaims the basic rate. Relief above that is delivered by increasing your rate limits by the contribution, which reaches you through a Self Assessment return or an adjustment to your tax code. On £110,000 of income, a year's contribution here leaves £3,000.00 to claim; on £45,000 it leaves £0.00. Note where it goes: the claimed relief comes back to you as tax you did not pay, not into the pension, so the projection on this page counts only the money that actually reached the SIPP.
- Can I pay into a SIPP if I do not work?
Yes, up to the basic amount of £3,600 gross a year, which is a limit on relief rather than on contributions. Somebody with no relevant UK earnings can pay £2,880.00 in over a year and the provider will add £720.00, having paid no tax at all. Relevant UK earnings are broadly employment income and trading profits — a pension already in payment, the state pension and rental income are all taxed as income and none of them count, which catches out people who retire early and keep contributing.
- Does starting earlier really make that much difference?
On the arithmetic, yes, and the reason is that the last years of a long run are the ones with the biggest balance compounding. £300.00 a month for 30 years puts £135,000.00 into the SIPP and reaches £282,580.85 on the assumption this page opens with; the same contribution for 15 years puts in £67,500.00 and reaches £96,011.15. Half the contributions, far less than half the pot. That gap is entirely the assumption — at a growth rate of nothing the two columns would move together — which is why it is shown as a table of terms rather than asserted as a rule.
- What is the difference between a SIPP and a workplace pension?
Mostly who chooses the investments and how the relief arrives. A SIPP is yours: you choose the provider and what it holds, and it is a relief-at-source scheme, so basic-rate relief is added by the provider and anything above that is yours to claim. Most workplace schemes use a net pay arrangement instead, where the contribution comes out of your salary before tax and relief lands at your own rate automatically with nothing to claim. The tax treatment of the pot at the other end is the same. What a workplace scheme usually has and a SIPP does not is an employer contribution, which is money this page cannot show you because it is a term of a job rather than a rule of the tax system.
- Does this calculator include charges?
One charge: a percentage of the value taken every month, which is what a platform or account fee usually is. It is included in the projection rather than deducted at the end, so it compounds against you exactly as it does in a real account — and it takes its largest bite in the final years, when the pot is biggest. On the default figures the charge takes £26,222.68 over the term. Real accounts add fund charges, dealing costs and sometimes a flat fee, and some cap the percentage above a certain value; none of that is modelled, and each of them makes the pot smaller than the figure shown.
- What does the calculator show on the figures it opens with?
£500.00 a month leaving the account becomes £625.00 in the SIPP, on top of £50,000 already there. A year's contribution attracts £4,500.00 of relief and so costs £3,000.00. At 5.00% a year for 25 years, with a 0.45% charge, the pot reaches £495,012.74 — £123,753.19 of it tax-free and £371,259.55 taxable. That pot figure is an assumption compounded, not a balance.